1. Field of the Invention
The present invention relates generally to a system and method for mixing and dispensing fluids used in processing x-ray film, and more particularly to apparatus and method for flushing residual film processing chemicals from portions of the mixing and dispensing system.
2. Prior Art
When a medical diagnosis is accomplished with x-ray examination, it is often desirable to complete the examination during a single visit of a patient to a diagnostic x-ray room. Recalling patient to repeat or supplement an examination is undesirable for a number of reasons. Time is lost in obtaining the information necessary for proper medical diagnosis. Repetition of some procedures such as those requiring catheter insertion can increase patient risk. Patient discomfort and anxiety can be quite acute if the patient is severely ill or uncomfortable. Inefficient utilization of the x-ray equipment can result from unnecessary repetitions of the procedures.
With modern medical diagnostic procedures it is often desirable to develop and preliminarily examine a radiograph while the patient remains at an exposure station in a diagnostic x-ray room. This enables the satisfaction of the attending physician that a given x-ray examination procedure has been successfully completed, or alternatively that, for some reason, it must be augmented by repetition or by a further radiographic procedure.
Where radiographs are to be inspected while a patient remains at an exposure station, fast film processing has come to be considered a vitally necessary part of medical x-ray diagnostic procedures. To achieve high rates of operation, film processors have been developed which automatically process an exposed sheet of x-ray film by mechanically feeding the sheet of film in sequence through baths of developer and fixer solutions, and then by washing and drying the film sheet. The time required for completely processing a radiograph is in the neighborhood of one and one half minutes or less.
Chemicals which perform the developing and fixing are consumed by use and degrade with time. With manual film processing, a skilled technician can compensate for depletion in solution concentrations by retaining films in the solutions for longer periods of time. With automatic processors, on the other hand, processing times are substantially constant and as a consequence, if solution concentrations are allowed to become depleted, the inevitable result is poor quality processing.
Accordingly, providing fast film processing of the requisite high quality and at the high volumes which are often encountered in busy hospitals depends on the continual provision of fresh, clean, and properly mixed chemicals. As the sheets of the film are transported through the baths, solution is carried away by the sheets and chemicals are consumed. Thus, fresh chemicals are required if desired processing quality is to be maintained and chemical replenishment is a necessity.
The developer and fixer solutions have relatively short shelf-lives; accordingly, it is desirable to mix the developer and the fixer solutions (1) near the location of the film processor and (2) at times immediately prior to the demand for them by the film processor.
In hospitals and clinics it is quite common for an attendant to mix the developer and fixer solutions manually. In this manual procedure the operator pours measured amounts of the chemical components and water into a mixing tank and then manually agitates the solution.
Manual mixing procedures have several drawbacks. Errors in proportioning the chemistry are common. Manual mixing is slow and messy. An attendant must maintain vigilance over the supplies of replenishment fluid in storage tanks.
In an attempt to alleviate these problems, the prior art has proposed chemical mixing systems which were intended to automatically mix developer and fixer solutions in proper concentrations and to dispense them to one or more film processors.
An automatic fluid mixing and dispensing system similar to the type into which the present invention is designed to be incorporated is described in U.S. Pat. No. 4,103,358, issued on Jul. 25, 1978 to Gachi, et al., and entitled "Fluid Mixing And Dispensing System". This patent is hereby expressly incorporated by reference.
In that patent, an improved technique for expeditiously mixing film processing chemicals is described wherein a plurality of bottles, each of a different size and containing a different film processing chemical, are used. The bottles include openings each sealed by a foil septum and which are accessible so that each bottle may be opened by piercing its foil septum.
According the '358 patent, the bottles, each containing a quantity of concentrated film processing chemical, are supported in an inverted orientation prior to piercing. The fluid mixing and dispensing system includes a plurality of tubular piercers with sharp ends pointing upwardly. Each piercer is aligned with the opening of a different one of the chemical containing bottles.
The piercers are vertically movable in ganged fashion by means of a piston mechanism attached to the piercers by way of a common supporting manifold. While the bottles are being positioned in their stationary inverted orientations prior to piercing, the piercers are in a lowered position such that they do not contact the foil septum of the bottles. After the bottles are positioned for opening, and opening is desired, the piston mechanism is actuated which raises the piercers so that each one penetrates the foil septum, or cover, which seals an unopened bottle.
After piercing, the chemicals within each bottle drain by gravity and are carried for mixing together in a common tank or reservoir, to which water is added, effecting agitation and desired dilution of the concentrated chemicals into a properly proportioned batch of fresh film processing chemical. This process, and apertures for carrying it out, is explained in detail in the incorporated '358 patent.
The system described in the '358 patent also included a rinse mechanism for directing water against a surface portion of the bottle supporting structure. See particularly the portions of the described system indicated at references characters 64 and 62 in the '358 patent.
The system into which the present invention is incorporated may optionally differ somewhat from the system of the '358 patent, in that the system described in the patent incorporated a carrier for holding the bottles, while the system into which the present invention is designed to be incorporated optionally does not utilize such a carrier. Rather, the system in which the present invention is embodied optionally relies upon a stationary template as a stationary apertured template for maintaining the bottles in a stable, inverted orientation prior to and after piercing.
While the system of the '358 patent has proven generally effective in accomplishing its purposes, a problem has arisen due to the tendency of some of the concentrated chemicals to remain in the bottles or to crystalize, about the piercer surfaces, causing them to adhere to the interior walls of the bottles and to the piercer surfaces. This results in incomplete emptying of the film processing chemicals from the bottles, undesirably weakening the concentration of the final mix. The crystalized material can also obstruct or restrict fluid flow through the hollow piercers, further limiting drainage of the chemicals from the bottles into the desired batch.
It is an object of this invention to provide a flush means and method for removing crystallized chemicals adhering to the interior surfaces of the bottles and to the surfaces and hollow cores of the tubular piercers, to facilitate complete discharge of all film processing chemicals from each bottle, and to minimize fouling of the fluid mixing and dispensing system by substantially eliminating crystalline deposits.